An exile Tibetan monk gestures as he makes a point in a dialectics debate with another monk, sitting right, at the Kirti monastery in Dharmsala, India, Monday, January 18, 2016. The debate is an essential part of their training as Buddhist monks. (Photo by Ashwini Bhatia/AP Photo)

Singer Rihanna poses at amfAR's fifth annual Inspiration Gala in Los Angeles, California October 29, 2014. (Photo by Mario Anzuoni/Reuters)

Actors Aubrey Plaza and Matthew Gray Gubler pose for a portrait during the 2014 Sundance Film Festival at the Getty Images Portrait Studio at the Village At The Lift on January 19, 2014 in Park City, Utah. (Photo by Larry Busacca/AFP Photo)

Supporters of former Democratic presidential candidate Bernie Sanders hold up posters at a “Black Men For Bernie” rally to gain support for third party candidates and protest the DNC during the 2016 Democratic National Convention on July 27, 2016 in Philadelphia, Pennsylvania. (Photo by Patrick T. Fallon/AFP Photo)

A jockey takes part in a traditional cattle race or “Pacu Jawi”, to mark the end of the rice harvest in Tanah Datar, West Sumatra, Indonesia, August 13, 2016 in this photo taken by Antara Foto. (Photo by Hafiz Mubarak A./Reuters/Antara Foto)

Local villagers fall onto the ground from an ox-cart as they ride to rid evil spirits from their village at Pring Ka-ek village, Cambodi. (Photo by Heng Sinith/AP Photo)

An officer reviews members of the honor guard as they line up before a welcoming ceremony for visiting Mozambique's President Filipe Jacinto Nyusi at the Great Hall of the People in Beijing, Wednesday, May 18, 2016. (Photo by Mark Schiefelbein/AP Photo)

The anthropomorphic robot named hitchBOT sits on the shoulder of Highway 102 to begin its 6000 kilometer cross country journey outside of Halifax, Nova Scotia, July 27, 2014. The hitch hiking robot is part of a social experiment to see if drivers will pick up and drop off the robot in one piece to an art gallery in Victoria, British Columbia. (Photo by Paul Darrow/Reuters)